The present invention relates to compounds, pharmaceutical compositions based thereon, and a method of treating senility or of reversing amnesia. More particularly, it is concerned with certain related 5-oxo-3-(unsubstituted-phenyl)- or 5-oxo-3-(substituted-phenyl)-2-pyrrolidinepropanoic acids and 5-oxo-.beta.-(unsubstituted-phenyl)- or 5-oxo-8-(substituted-phenyl)-2-pyrrolidinepropanoic acids, their pharmaceutically acceptable esters and metal and amine cation salts, pharmaceutical compositions employing these compounds, and a method of treating senility or of reversing amnesia.